The present invention relates generally to a drying machine and relates particularly, though not exclusively, to an air cushioned vehicle or machine adapted to dry a playing surface of sporting fields or the like.
There are known machines for drying the playing surface of sporting fields. These machines are driven or pushed across the playing surface with wheels and/or rollers contacting the surface. An inherent problem with drying machines of this construction is that the weight of the machine on the porous grass surface tends to draw water to the top surface of the grass. That is, the machine itself will promote moisture on the playing surface which must be dried or removed together with the initial surface moisture. It is understood that larger drying machines may provide adequate drying although to some extent the increased weight further exasperates the drawing of water from below the surface. Furthermore, these relatively large drying machines can be difficult to transport from site to site. Another technique conventionally adopted to dry sporting fields utilises a helicopter which drives moisture from the playing surface. However, this technique is not widely used as the charter or operation of helicopters is relatively expensive. Furthermore, both the helicopter and more conventional drying machines disperse the surface moisture and water rather than collecting it.
According to the present invention there is provided a drying machine comprising:
a frame structure including a perimeter wall which defines an underlying cavity;
means for propelling air into the cavity at a relatively high velocity wherein the frame structure is adapted to hover across a surface to be dried and the high velocity air is effective in driving moisture or water from the surface and outwardly of the cavity, said propelling means being operatively coupled to the frame structure; and
means for diverting air together with the moisture or water driven from the surface, said diverting means being operatively coupled to the frame structure whereby the air and moisture or water driven from the surface can be collected externally of the cavity and within the drying machine.
Typically the diverting means includes a diversion element mounted to the frame structure and at least in part defining an auxiliary flow passage whereby the high velocity air from the underlying cavity is directed through the auxiliary flow passage so as to promote the collection of the air and moisture or water within the machine. More typically the diversion element is operatively coupled to a forward edge of the frame structure of the drying machine.
Preferably the drying machine also comprises means for collecting the air and moisture driven from the surface. More preferably said collecting means includes a screen element connected to the frame structure to define an enclosed space forward of the frame structure whereby the diverted high velocity air flowing through the auxiliary flow passage deflects the air and moisture or water driven off the surface and into the enclosed space.
Typically the collecting means further comprises one or more tanks mounted to the frame structure, said tanks operatively communicating with the screen element for collection of a moisture fraction of the air and moisture driven from the surface. More typically the collecting means includes a series of vanes or louvres connected to the frame structure and disposed above one or more of the tanks to promote condensation of the moisture into said tanks.
Preferably the propelling means includes a motor coupled to a fan which is arranged to provide the required high velocity downward airflow for hovering of the frame structure. More preferably the motor is coupled to the fan via a gearbox.
Typically the drying machine includes a flexible skirt mounted about and at least partially defining the perimeter of the frame structure, said flexible skirt being configured to substantially enclose the cavity of the frame structure to provide an air cushion for the machine.
Preferably the drying machine includes a handle connected to the frame structure and designed to permit movement of the machine by hand.
Generally the drying machine is adapted for drying of a grassed surface such as a sporting field.